The present invention relates to an electric guitar and, more particularly, to an electronic vibrato apparatus capable of accurately designating pitch widths for a vibrato effect in a multistep manner using a plurality of operation elements for designating different units of pitch width.
An electric guitar disclosed in Japanese Utility Model Laid-Open No. 62-38699 is known as a conventional electric guitar of this type. A schematic description of this electric guitar will be made below. The electric guitar disclosed in Japanese Utility Model Laid-Open No. 62-38699 serves to generates a vibrato effect by electronic signal processing. According to this electric guitar, an analog signal output from an electromagnetic pick-up is sampled with a first sampling frequency, and then a digital signal corresponding to each of the sampled analog signal is temporarily stored in a memory. The digital signal stored in the memory is read out and converted into an analog signal again. This analog signal is sampled with a second sampling frequency to form an output signal. This second sampling frequency is selected on the basis of a control signal which is supplied from a rotary switch and can be changed stepwise. The rotary switch can designate a pitch width for vibrato at an interval of a semitone. Therefore, in this electric guitar, the second sampling frequency can be increased/decreased stepwise by operating the rotary switch, and the pitch of a musical tone generated in accordance with a ratio of the first sampling frequency to the second sampling frequency can be changed.
Generally, when a vibrato is provided to a musical tone, it is perceived as if the musical tone were vibrated with its pitch (fundamental pitch) kept constant. However, if the width of change in pitch is excessively large, changes in fundamental pitch can be clearly perceived. As a result, the vibrato effect to be originally desired cannot be obtained.
According to a vibrato apparatus in the above-described conventional electric guitar, since the width of a vibrato is designated in unit of pitch width corresponding to a semitone via the rotary switch, it is necessarily difficult for a performer to designate an arbitrary width of a vibrato by the rotary switch. In the worse case, the pitch width designated by the rotary switch becomes larger than a desired pitch width, and it is perceived that the fundamental pitch of a musical tone is changed in the above-described manner, thereby failing to obtain the vibrato effect to be originally desired.